Giant Stroke, Superelastic Carbon Nanotube Aerogel Muscles
A. Aliev, J. Oh, M. Kozlov, A. Kuznetsov, S. Fang, A. Fonseca, R. Robles, M. Lima, M. Haque, Y. Gartstein, M. Zhang, A. Zakhidov and R. Baughman
University of Texas at Dallas, US
Keywords: carbon nanotube, artificial muscle
Abstract:We have developed a fundamentally new type of artificial muscle, which operates in air to generate giant strokes and stroke rates of 220% and 3.7 x 104 %/s, respectively. Charge-driven resonant and dc linear actuation result for volt to kilovolt drive voltages, and temperatures from below 80 K to above 1900 K. Using mechanical and electrical resonances, these artificial muscles provided ±30% oscillatory actuation at a kHz when driven by 10 VRMS. In the high modulus sheet direction, where actuator stroke is a few percent, stress generation was 32-fold higher than the sustainable value for natural skeletal muscle. Actuation in this direction differs in sign from that in sheet width and thickness directions. We theoretically explain this sign reversal using giant observed Poisson’s ratios of up to 15, which provide a negative linear compressibility for the sheets. The observed dependence of actuation on boundary constraints, applied voltage, and sheet thickness are also theoretically explained.